The biological response of hairy roots to O2 levels in bioreactors

Summary The efficient exchange of gases between roots and their environment is one of the biggest challenges in bioreactor design for transformed root cultures. Gas-phase reactors can alleviate this problem as well as provide a new tool for studying the biological response of roots and other differentiated tissues to changes in the gas phase composition. In our comparison of liquid- and gas-phase reactors, roots grown in liquid (shake flasks or bubble column reactors) are shown to be under hypoxic stress. Roots grown in a gas-phase reactor (nutrient mist), while not hypoxic, produced 50% less biomass. These results suggest that the response of the tissues to gas phase composition are complex and need further study.     

Definition of the Native and Denatured Type II Collagen Binding Site for Fibronectin Using a Recombinant Collagen System

Interaction of collagen with fibronectin is important for extracellular matrix assembly and regulation of cellular processes. A fibronectin-binding region in collagen was identified using unfolded fragments, but it is not clear if the native protein binds fibronectin with the same primary sequence. A recombinant bacterial collagen is utilized to characterize the sequence requirement for fibronectin binding. Chimeric collagens were generated by inserting the putative fibronectin-binding region from human collagen into the bacterial collagen sequence. Insertion of a sufficient length of human sequence conferred fibronectin affinity. The minimum sequence requirement was identified as a 6-triplet sequence near the unique collagenase cleavage site and was the same in both triple-helix and denatured states. Denaturation of the chimeric collagen increased its affinity for fibronectin, as seen for mammalian collagens. The fibronectin binding recombinant collagen did not contain hydroxyproline, indicating hydroxyproline is not essential for binding. However, its absence may account, in part, for the higher affinity of the native chimeric protein and the lower affinity of the denatured protein compared with type II collagen. Megakaryocytes cultured on chimeric collagen with fibronectin affinity showed improved adhesion and differentiation, suggesting a strategy for generating bioactive materials in biomedical applications.     

The interaction between actin and FA fragment of diphtheria toxin

Actin protein has many other cellular functions such as movement, chemotaxis, secretion and cytodiaresis. Besides, it have structural function. Actin is a motor protein that it has an important role in the movement process of toxin in the cell. It is known that F-actin gives carriage support during the endosomal process. Actin is found in globular (G) and filamentous (F) structure in the cell. The helix of actin occurs as a result of polymerisation of monomeric G-actin molecules through sequential rowing, is called F-actin (FA). Actin interacts with a great number of cellular proteins along with cell skeleton and plasma membrane. It is also known that some bacterial toxins have ADP-ribosylation affect on actin. Diphteria toxin is the part which has the FA enzymatic activity corresponding the N-terminal section of the toxin, which inhibits the protein synthesis by ADP-ribosylating the elongation factor 2 in the presence of NAD. FA, taken into the cell by endocytosis inhibits protein synthesis by ADP-ribosyltransferase activity and breaks the cytoskeleton. In the studies both in vitro and in vivo, actin with interaction FA of diphteria toxin has been yet to be fully elucidated. The aim of this study was to determine the three dimensional structures of actin with interaction FA of diphteria toxin by the amprical methods and in paralel with the computing technology, theoretical methods have gained significant importance. In our study, actin with interaction FA of diphteria toxin has been determined as the most possible interaction area with the theoretical method; analogy modelling. This area has been closed in the presence of polypeptides and FA-actin interactions have been tested with the gel filtration chromatography techniques. As a result of the findings, we found that 15 amino acid artificial peptides (DAMYETMAQACAGNR) corresponding to 201–215 amino acid residues of FA interacts with G-actin and closes this area. Secondly, in the model formed with the analogy modelling, it appears that the most possible interaction area is between FA (tyr204) and G-actin (gly48). Results obtained from both theoretical and experimental data support the idea that the interaction occurs in this area.     

Endogenous ADP-ribosylation for eukaryotic elongation factor 2: evidence of two different sites and reactions

Eukaryotic elongation factor 2 can undergo ADP-ribosylation in the absence of diphtheria toxin under the action of an endogenous transferase. The investigation which aimed to gain insight into the nature of endogenous ADP-ribosylation revealed that this reaction may be, in some cases, due to covalent binding of free ADP-ribose to elongation factor 2. Binding of free ADP-ribose, and NAD- and endogenous transferase-dependent ADP-ribosylation were suggested to be distinct reactions by different findings. Free ADP-ribose could bind to elongation factor 2 previously subjected to ADP-ribosylation by diphtheria toxin or endogenous transferase. The binding of free ADP-ribose was inhibited by neutral NH2OH, L-lysine and picrylsulfonate, whereas endogenous ADP-ribosyltransferase was inhibited by NAD glycohydrolase inhibitors and L-arginine. The ADP-ribosyl-elongation factor 2 adduct which formed upon binding of free ADP-ribose was resistant to neutral NH2OH, but decomposed almost completely upon treatment with NaOH. The product of endogenous transferase-dependent ADP- ribosylation was partially resistant to NH2OH and NaOH treatment. Moreover, this reaction was reversed in the presence of diphtheria toxin and nicotinamide. Both types of endogenous ADP-ribosylation gave rise to inhibition of polyphenylalanine synthesis. This study thus provides evidence for the presence of two different types of endogenous ADP-ribosylation of eukaryotic elongation factor 2. The respective sites involved in these reactions are distinct from one another as well as from diphthamide, the site of attack by diphtheria toxin.     

Duration of renal failure as risk factor for conjunctival squamous metaplasia

OBJECTIVE: To assess ocular surface changes in patients with chronic renal failure (CRF), to compare the results with the duration of illness. STUDY DESIGN: Impression cytology from 48 patients with CRF on regular hemodialysis and 16 age- and sex-matched control subjects were studied. Specimens were taken from the temporal bulbar conjunctiva using cellulose acetate filter paper. RESULTS: Among the patients with CRF who were ill for 0-10 years, 25 patients (78.1%) disclosed grade 0-1, and 7 patients (21.9%) disclosed grade 2-3 cytologic changes, whereas in those with the duration of CRF > 10 years, 9 patients (56.2%) had grade 0-1 and 7 patients (43.8%) had grade 2-3 changes. Specimens from the control group revealed 93.8% grade 0-1 and 6.2% grade 2-3 changes (p < 0.05). CONCLUSION: The ocular surfaces of patients with CRF differ significantly from those of normal individuals, and the severity of conjunctival changes is related to the duration of CRF.     

Lack of association between prohibitin 3' untranslated region C-->T polymorphism and breast cancer in a Turkish population

The 3' untranslated region (3'UTR) of the prohibitin gene has a positive effect on arresting cell proliferation between G1 and S phases and inhibits DNA synthesis. A C-to-T transition within this region creates a variant that alters mRNA function and has been shown to be associated with an increased breast cancer risk among young North Americans who are under 50 years and have at least one first-degree relative with breast cancer. We carried out a population-based case-control study to assess whether this association exists in Turkish women. We examined 106 breast cancer patients and 154 healthy controls by PCR and restriction fragment length polymorphism analysis. In the prohibitin 3'UTR, we did not detect a difference in CT/TT genotype frequency (p = 0.694; odds ratio [OR], 1.106; 95% confidence intervals [CI], 0.659-1.86) or in C/T allele frequency (p = 0.850; OR, 1.043; 95% CI, 0.667-1.62) between the all breast cancer patients and the controls. The results did not change in subgroups defined by age or family history. Hence our results do not lend support to the hypothesis that this polymorphism contributes to risk of breast cancer. The prohibitin T variant is not associated with the risk of breast cancer in Turkish women.     

The importance of association between angiotensin-converting enzyme (ACE) Gene I/D polymorphism and diabetic peripheral neuropathy

Background

Diabetic peripheral neuropathy (DPN) is a microvascular complication of diabetes mellitus (DM) due to decreasing quality of life. In the present study, it is aimed to evaluate angiotensin-converting enzyme (ACE) Gene I/D polymorphism in Turkish population.

Materials and methods

Two hundred and thirty-five DPN patients and two hundred and eighty-one controls were enrolled in this study. Genomic DNA was isolated and genotyped using polymerase chain reaction (PCR) analyses for the ACE gene I/D polymorphism.

Results

Baseline characteristics of the DPN patients according to ACE genotypes were similar, except for history of hypertension. The frequency of II genotype was significantly higher in patients with positive history of hypertension than the patients with negative history of hypertension (p = 0.013). DD genotype of I/D polymorphism was found to be a susceptibility factor for DPN in homozygous form (p = 0.032). According to allele frequencies, D allele of I/D polymorphism was found to be a susceptibility factor for DPN (p = 0.031).

Conclusion

ACE gene I/D polymorphism may research in DM patients to determine genetic predisposition for DPN. It can be useful for taking early measures and avoiding DPN in a Turkish population.     

Influence of vanadium supplementation on oxidative stress factors in the muscle of STZ-diabetic rats

In recent years, the role of free radical damage consequent to oxidative stress is widely discussed in diabetic complications. In this aspect, the protection of cell integrity by trace elements is a topic to be investigated. Vanadium is a trace element believed to be important for normal cell function and development. The aim of the present study was to investigate the effect of vanadyl sulfate supplementation on the antioxidant system in the muscle tissue of diabetic rats. Diabetes was induced by intraperitoneal injection of streptozotocin (STZ, 65 mg/kg body weight) to male Swiss albino rats. The rats were randomly divided into 4 groups: Group I, control; Group II, vanadyl sulfate control; Group III, STZ-diabetic untreated; Group IV, STZ-diabetic treated with vanadyl sulfate. Vanadyl sulfate (100 mg/kg) was given daily by gavage for 60 days. At the last day of the experiment, rats were killed, muscle tissues were taken, homogenized in cold saline to make a 10% (w/v) homogenate. Body weights and blood glucose levels were estimated at 0, 30 and 60th days. Antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), glutathione-S-transferase (GST), as well as carbonic anhydrase (CA), myeloperoxidase (MPO) activities and protein carbonyl content (PCC) were determined in muscle tissue. Vanadyl sulfate administration improved the loss in body weight due to STZ-induced diabetes and decreased the rise in blood glucose levels. It was shown that vanadium supplementation to diabetic rats significantly decrease serum antioxidant enzyme levels, which were significantly raised by diabetes in muscle tissue showing that this trace element could be used as preventive for diabetic complications.     

Effects of Dietary Supplementation with Vitamin C and Vitamin E and Their Combination on Growth Performance,Some Biochemical Parameters,and Oxidative Stress Induced by Copper Toxicity in Broilers

This study investigated effects of dietary supplementation with vitamin C, vitamin E on performance, biochemical parameters, and oxidative stress induced by copper toxicity in broilers. A total of 240, 1-day-old, broilers were assigned to eight groups with three replicates of 10 chicks each. The groups were fed on the following diets: control (basal diet), vitamin C (250 mg/kg diet), vitamin E (250 mg/kg diet), vitamin C + vitamin E (250 mg/kg?+?250 mg/kg diet), and copper (300 mg/kg diet) alone or in combination with the corresponding vitamins. At the 6th week, the body weights of broilers were decreased in copper, copper + vitamin E, and copper + vitamin C + vitamin E groups compared to control. The feed conversion ratio was poor in copper group. Plasma aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase activities, iron, copper concentrations, and erythrocyte malondialdehyde were increased; plasma vitamin A and C concentrations and erythrocyte superoxide dismutase were decreased in copper group compared to control. Glutathione peroxidase, vitamin C, and iron levels were increased; aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and copper levels were decreased in copper + vitamin C group, while superoxide dismutase, glutathione peroxidase, and vitamin E concentrations were increased; aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase were decreased in copper with vitamin E group compared to copper group. The vitamin C concentrations were increased; copper, uric acid, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and malondialdehyde were decreased in copper + vitamin C + vitamin E group compared to copper group. To conclude, copper caused oxidative stress in broilers. The combination of vitamin C and vitamin E addition might alleviate the harmful effects of copper as demonstrated by decreased lipid peroxidation and hepatic enzymes.